Lifetime vibration dose correlates with severity of the neurological component of hand-arm vibration syndrome among tyre shop workers in Kelantan, Malaysia

Introduction. Cumulative lifetime exposure to vibration is believed to contribute to more severe complications of hand-arm vibration syndrome (HAVS). Objectives. To determine prevalence of the neurological component of HAVS and the correlation between lifetime vibration dose (LVD) and neurological severity of HAVS among tyre shop workers in Kelantan. Methods. The cross-sectional study involved 200 tyre shop workers from two districts in Kelantan. Part one data were collected in the field using a questionnaire and hand-arm vibration was measured. Part two involved a set of hand clinical examinations (Purdue pegboard, Semmes-Weinstein monofilament and two-point discrimination tests) carried out for neurological component severity staging. LVD for each worker was calculated from data gathered in part one. For workers who had neurological symptoms, staging according to Stockholm workshop scales was done according to part two data. The strength of correlation between LVD and neurological stages was then determined using Spearman correlation. Results. Prevalence of neurological component was 37%. Spearman correlation between LVD and the neurological stages showed a moderate positive correlation. Conclusion. Cumulative lifetime exposure to hand-transmitted vibration is likely to be related to neurological severity of HAVS and therefore must be considered when assessing workers' exposure to hand-arm vibration.